1. Field of the Invention
The present invention relates to a refrigerant composition that can replace chlorodifluoromethane (referred to as xe2x80x98HCFC-22xe2x80x99, hereinafter) which has been known to destroy the ozone layer of the Earth.
2. Description of the Background Art
Since chlorofluorocarbon (referred to as xe2x80x98CFCxe2x80x99, hereinafter) compounds were revealed as substances destroying the ozone layer of the Earth, they have been restricted in production and use according to the Montreal Protocol. In developed countries, the use of CFC compounds has already been banned since 1996. Not so much serious as CFC compounds, but HCFC compounds such as HCFC-22 have also been known to have considerable effects in causing damage to the ozone layer. For this reason, a restriction has been made to gradually reduce the use of HCFC compounds, and a plan has also been made to ban its use around 2030.
Many researches are being conducted to develop a substitute material for HCFC-22. Representative substitute materials for HCFC-22 are HFC-407C and HFC-410A proposed by the American Society of Heating Refrigerating and Air-conditioning Engineers (ASHRAE). HFC-407C is a refrigerant composition of HFC-32/125/134a in a ratio of 23/25/52 based on weight percent. Meanwhile, HFC-410A is a refrigerant composition of HFC-32/125 in a ratio of 50/50 based on weight percent.
In addition, U.S. Pat. No. 5,080,823 discloses a refrigerant composition of HFC-143a/propane, U.S. Pat. No. 5,211,867: HFC-125/143a, U.S. Pat. No. 5,234,613: HFC-32/propane, U.S. Pat. No. 5,236,611 of PFC-218/HFC-143a, U.S. Pat. No. 5,290,466: HFC-32/134a/134, U.S. Pat. No. 5,340,490: HFC-23/CO2 and HFC-23/116/CO2, U.S. Pat. No. 5,403,504: HFC-125/32, U.S. Pat. No. 5,429,740: HFC-23/134a U.S. Pat. No. 5,538,660: HFC-32/HFC-134a/FC-41 and HFC-32/HFC-134a/PFC-218, and U.S. Pat. No. 5,643,492: HFC-32/125/134a.
Also, Japanese Patent Laid-open Publication No. 172386/1991 discloses a refrigerant composition of HFC-32/125/143a, Japanese Patent Laid-open Publication No. 170594/1991: HFC-23/125/134a, Japanese Patent Laid-open Publication No. 170593/1991: HFC-23/143a/134a, Japanese Patent Laid-open Publication No. 170591/1991: HFC-23/143a/134a, Japanese Patent Laid-open Publication No. 170590/1991: HFC-125/134a/32, Japanese Patent Laid-open Publication No. 170589/1991: HFC-23/143a/152a, Japanese Patent Laid-open Publication No. 170588/1991: HFC-125/143a/134a, Japanese Patent Laid-open Publication No. 170585/1991: HFC-32/125/134a, Japanese Patent Laid-open Publication No. 170584/1991: HFC-23/134a/152a, Japanese Patent Laid-open Publication No. 170583/1991: HFC-125/143a/32, Japanese Patent Laid-open Publication No. 222893/1992: HFC-32/125, Japanese Patent Laid-open Publication No. 154887/1992: HFC-134/152a, Japanese Patent Laid-open Publication No. 117645/1993: HFC-23/134a/propane, Japanese Patent Laid-open Publication No. 117643/1993: HFC-125/134a/propane, Japanese Patent Laid-open Publication No. 65561/1994: HFC-23/152a/PFC-218, Japanese Patent Laid-open Publication No. 128872/1994: HFC-32/PFC-218, Japanese Patent Laid-open Publication No. 173462/1995: HFC-32/125-RC-318, Japanese Patent Laid-open Publication No. 173462/1995: HFC-143a/125/134a/heptane, Japanese Patent Laid-open Publication No. 176537/1996: PFC-218/RC-270/HFC-152a, Japanese Patent Laid-open Publication No. 151569/1996: propane/RC-270/HFC-134a, Japanese Patent Laid-open Publication No. 127767/1996: HFC-32/134a/RC-318, Japanese Patent Laid-open Publication No. 25480/1997: HFC-32/134a/125/isobutane, Japanese Patent Laid-open Publication No. 208941/1997: HFC-32/152a/125/RC-270, and Japanese Patent Laid-open Publication No. 221664/1997: HFC-125/143a/134a/RC-270.
Also, Korean Patent Laid-open Publication No. 91-9902 discloses a refrigerant composition of HFC-23/32/152a, HFC-23/125/152a, HFC-32/143a/152a, HFC-32/125/125a, HFC-23/143a/152a, Korean Patent Laid-open Publication No. 91-9903: HFC-23/32/134, HFC-23/32/134a, HFC-23/125/134, HFC-32/125/134, HFC-23/143a/134a, HFC-125/143a/134a, HFC-125/143a/134, Korean Patent Laid-open Publication No. 96-4485: HFC-32/23/134a, Korean Patent Laid-open Publication No. 96-701168: HFC-227ea/HFC-152a, Korean Patent Laid-open Publication No. 97-704853: HFC-134a/HCFC-124/butane.
Therefore, an object of the present invention is to provide a novel refrigerant composition that can be used as a substitute for HCFC-22, without containing a substance that destroys the ozone layer of the Earth.
The above and other objects of the present invention, as embodied and broadly described herein, are achieved by providing a refrigerant composition, comprising (a) a first constituent of difluoromethane (hereinafter referred to as xe2x80x98HFC-32xe2x80x99), (b) a second constituent of 1,1,1-trifluoroethane (hereinafter referred to as xe2x80x98HFC-143axe2x80x99), (c) a third constituent of 1,1-difluoroethane (hereinafter referred to as xe2x80x98HFC-152axe2x80x99) and (d) a fourth constituent selected from the group consisting of 1,1,1,2,3,3,3-heptafluoropropane (hereinafter referred to as xe2x80x98HFC-227eaxe2x80x99), isobutane (hereinafter referred to as xe2x80x98R-600axe2x80x99), 1,1,1,2,3,3-hexafluropropane (hereinafter referred to as xe2x80x98HFC-236eaxe2x80x99) and butane (hereinafter referred to as xe2x80x98R-600xe2x80x99).
Advantageously, the refrigerant composition of the present invention does not have any risk to damage the ozone layer, and therefore, there is no concern to be restricted in its use in the future. The above compounds that can be a constituent of the refrigerant composition of the present invention have already been produced, or research is actively conducted to produce them for later use. Their use is newly added through the present invention, and therefore they can be used more effectively.
The refrigerant composition of the present invention has been applied for a refrigeration system having a compressor, a condenser, an expansion valve and an evaporator to evaluate a coefficient of performance (COP), a volumetric capacity (VC) of the refrigerant and pressures in the compressor and evaporator. The novel refrigerant composition proposed by the present invention has been evaluated to have almost the same level in performance compared with HFC-407C or HFC-410 that has been proposed as a substitute refrigerant for HCFC-22, so that it can be used as a substitute material for HCFC-22.
It is preferred that the refrigerant composition of the present invention comprises the first constituent in the range of 30-70 wt. %, the second constituent in the range of 10-50 wt. %, the third constituent in the range of 10-50 wt. % and the fourth constituent in the range of 5-30 wt. %. Preferred embodiments of the refrigerant composition of the present invention comprising specific compounds will now be described.
Where the refrigerant composition comprising HFC-32, HFC-143a, HFC-152a and HFC-227ea, the contents of constituents are in the ranges of 30-70 wt. %, 10-50 wt. %, 10-40 wt. % and 10-30 wt. %, respectively, and preferably, in the ranges of 40-60 wt. %, 20-40 wt. %, 20-30 wt. % and 15-25 wt. %, respectively.
Where the refrigerant composition comprising HFC-32, HFC-143a, HFC-152a and R-600a, the contents of constituents are in the ranges of 30-70 wt. %, 10-50 wt. %, 10-40 wt. % and 5-15 wt. %, respectively, and preferably, in the ranges of 40-60 wt. %, 20-40 wt. %, 20-30 wt. % and 8-12 wt. %, respectively.
Where the refrigerant composition comprising HFC-32, HFC-143a, HFC-152a and HFC-236ea, the contents of constituents are in the ranges of 30-70 wt. %, 10-40 wt. %, 10-40 wt. % and 10-20 wt. %, respectively, and preferably, in the ranges of 20-60 wt. %, 20-30 wt. %, 20-30 wt. % and 13-17 wt. %, respectively.
Where the refrigerant composition comprising HFC-32, HFC-143a, HFC-152a and R-600, the contents of constituents are in the ranges of 30-70 wt. %, 10-40 wt. %, 10-50 wt. % and 5-12 wt. %, respectively, and preferably, in the ranges of 40-60 wt. %, 20-30 wt. %, 20-40 wt. % and 7-10 wt. %, respectively.